Adding a discard matter package and Thopter Sword combo.

Scrounging Skyray having evasion and cycling means it’ll very rarely be a bad draw in nearly any deck, and once you add a few discard outlets, this card can get outta control pretty quickly. Kitesail Larcenist is a bit underwhelming, the body isn’t
big enough and the removal isn’t permanent enough, so I’m making this cut.

Marauding Mako is along the same lines as the Skyray, losing flying but being half the cost, to give another cycler/payoff to the archetype. The spells matter cards are usually a bit underwhelming, and I needed to make room, so first on the chopping block is Dragon's Rage Channeler. Delirium isn’t always a guarantee, and although the card selection is nice, adding a few cyclers has a similar effect.

Blazing Rootwalla is close to playable without a discard outlet already, and once you get to play it for free it gets much better. I had thought about adding OG Squee into this spot, as just a card you can discard many times over several turns, but am gonna try Rootwalla first. Monastery Swiftspear is always a fine card, but without a barrage of spells to follow it up it can be a little underwhelming.

Scrapwork Mutt is a discard enabler, a fine card to discard because of unearth, and also adds an extra artifact for the artifact decks as well. A solid role-player even if it’s a bit unexciting. Rimrock Knight is one of the weaker adventure cards in cube, and although I liked having an extra pump spell, not boosting toughness mostly made it as a Lava Spike type card anyways.

Ivora, Insatiable Heir is both a payoff and enabler, and even if they remove it right away, it still left behind a blood to use anyways. Trample really pushes this card into the must answer threat that the discard deck will want. It’s also just a fine card on it’s own as well. Searslicer Goblin is just not as good as it’s Rabblemaster variants, so it’s the cut here.

Conspiracy Theorist might not have quite enough to make it in the archetype, but being both enabler and payoff is worth testing at least. Slickshot Show-Off has the same problems as Swiftspear, so it’s also getting the axe.

Lightning Axe is a great removal spell, assuming you can get value out of the discard, similar to Bone Shards and Bitter Triumph. Monstrous Rage is one of the better pump spells printed, but cube is just too hostile towards pump spells in general, so I’m making this swap.

Selesnya is a tough guild because the gold cards are generally strong, but the archetype overall isn’t very good. I wanna try Treebeard, Gracious Host. Ward 2 and an ETB make it decent against both spot and mass removal, trample means it’s hard to chump, it makes it’s own food so even if you take the next turn off to grow it, you at least gained some life to stabilize, and once you combine it with any other life gain, it can start to really take over a game. Dryad Militant was essentially a Savanah Lion, and with so many great Lions in white (and even green) it’s really not worth a slot anymore.

Rielle, the Everwise is another good payoff, turning cards like Faithless Looting into Recalls. It does have a spells matters half of text as well, but that's just extra sauce on top of a decent card already. Sprite Dragon is one of the better spells matters payoffs, as the counters stick around, but something needed to give way.

Thopter Foundry and Sword of the Meek add a nice little combo at a pretty low cost to cube slots, as Sphinx of the Steel Wind and Grafted Wargear haven’t been seeing much play lately (while also getting a color hoser out of the cube).

Containment Construct was in the cube previously, but I think with more support now it can truly earn its spot. Obsidian Obelisk was a fine mana rock, but entering tapped made it usually worse than the other options available.